| 摘要 |
Electronic grade boron in the form of free-flowing, bead-like particles, and suitable for use in continuous and semi-continuous Czochralski systems for preparing doped, single crystal silicon, said particles having an average size within the range of from 500 to 700 microns, a size distribution of less than 100 - 150 microns, and a purity of at least 99.9995 percent. A process for preparing it, comprising contacting in a fluidized bed, (a) boron seed particles having a size within the range of from 150 to 200 millimicrons with (b) a gas comprising a thermally decomposable boron hydride, such as diborane ou decaborane, said seed particles being above the decompostition temperature of said hydride, whereby deposition of boron on said seed particles takes place until said particles have grown to an average size within the range of from 500 to 700 microns. |
